Bubble machine



FIG. 1 is a front perspective view of a bubble machine showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The dot-dash-dot lines define the bounds of the claimed design and form no part thereof. All other broken lines illustrate portions of the bubble machine that form no part of the claimed design. 

CLAIM The ornamental design for a bubble machine, as shown and described. 